﻿#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<math.h>
int main()
{
	int n = 0;
	int m = 0;
	while (scanf("%d %d", &n, &m) != EOF)
	{
		double sum = n;
		double M = n;
		for (int i = 0; i < m - 1; i++)
		{
			double d = sqrt(M);
			M = sqrt(M);
			sum += d;
		}
		printf("%.2lf\n", sum);
	}

	return 0;
}